Fig. 5

Anti-L1 antibody and cyclic RGD treatment reduces cell attachment and neurite outgrowth. a Reduced neurite outgrowth of SCNs was observed for each L1-Fc presentation (L1-Fc/PDL, L1-Fc/PA/PDL, and L1-Fc/PA) when the surface was pretreated with a monoclonal anti-L1 antibody. b SCNs cultured on L1-Fc/PA treated thin films exhibited a drastic decrease in neurite outgrowth compared to SCNs cultured on L1-Fc/PDL and L1-Fc/PA/PDL treated thin films when the anti-L1 antibody directed against the second Ig-like domain was added, suggesting that the epitope to which the L1 antibody binds is more exposed due to an outward display of L1-Fc presented from PA. c Dose-dependent reduction in cell attachment was observed in SCNs pretreated with cyclic RGD peptide prior to plating onto the different L1-Fc containing substrates. SCNs cultured on L1-Fc/PA treated thin films exhibited the greatest reduction in cell attachment indicating that L1-Fc presented from PA strongly interacts with α_vβ₃ integrins, which was interrupted by the presence of cyclic RGD peptide. Cell attachment on control substrates was not affected. d Similar to cell attachment, neurite outgrowth of SCNs was greatly diminished, in a dose-dependent manner, in the presence of cyclic RGD peptide. The greatest inhibition of neurite outgrowth, compared to untreated SCNs, was observed in SCNs cultured on L1-Fc/PA thin films, where as little as 1 μg/ml of cyclic RGD peptide inhibited cell attachment by 80%. Addition of 10 μg/ml of cyclic RGD peptide also resulted in a decrease in average neurite length of SCNs cultured on L1-Fc/PA/PDL coated thin films, although the effect was less prominent. The average neurite length of SCNs cultured on L1-Fc/PDL was not affected by any concentration of cyclic RGD, similar to the controls. Scalebar 75 μm. SCNs spinal cord neurons, PDL poly-d-lysine, PA protein A (* denotes p < 0.05, ** denotes p < 0.01)